General theory of force and mass reductions with examples from existing machines
A 1907 mechanical engineering thesis by Alwin Louis Schaller, submitted at the University of Illinois, working out force and mass reductions in linkages and machine parts for engineering readers. The 33 plates are hand-inked diagrams on toned paper—vector arrows, dashed construction lines, outlined rigid bodies, circles and triangles labeled with single letters and calculus notation—useful as loose, handwritten-looking technical line art and arrow vocabulary.
